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can scarcely be conceived without assuming ample, that if the resultant attraction on an a force of repulsion instead of attraction be- oil molecule at the surface is directed across tween molecules of the liquid.

the boundary from the oil side toward the But he surely can not mean to question the water, that a water molecule at the surface existence of negative surface tension at a sur- being in the same situation with respect to the face between a liquid and solid, for how other- surrounding molecules will be urged in the wise are we to explain the most familiar facts same direction. In other words, we can hardly in capillarity. Is it not negative surface ten- imagine a particle of one sort in the surface as sion which causes the water to rise in a capil- being drawn in one direction by the attraclary tube, or against a glass wall, and causes tion of all the surrounding particles on both a drop of oil to expand indefinitely over a glass sides of the surface, while a similarly situated plate? Is it not the greater negative surface particle of the other sort would be drawn in tension in the oil-glass surface which causes the opposite direction. the film to expand against the contractile force, We may assume then that at a surface beor positive surface tension of the oil-air sur- tween two liquids, particles on one side are face?

urged away from the surface, while those on Nor does it appear to be necessary to sup- the other side are urged toward it. That is, pose a repulsive force between molecules of the there are two influences, one tending to conliquid in order to account for the existence of tract the surface and the other to expand it. such a negative tension, for if the resultant If the first is predominant there is positive force of attraction on a particle of liquid near surface tension, this is the ordinary case where the surface, due to all particles on both sides diffusion does not take place, as with water-oil of the surface lying within the range of sen- or water-mercury. sible molecular attraction, is directed away If the second is predominant the surface from the surface and towards the interior of tends to expand indefinitely, and the limit the liquid, the particle will tend toward the would seem to be reached only when one interior and we shall have positive surface liquid is uniformly diffused throughout the tension but if the resultant attraction is tow- other. In this case diffusion is to be expected ard the surface there will be negative sur- also from the consideration that if particles face tension.

in the one liquid are drawn so powerfully towIn case of an air-liquid surface the attrac- ards the other as to force the expansion of the tion of neighboring liquid particles upon a second liquid in opposition to its contractile particle in the surface is so much greater than tendency, it seems probable that they will be any opposing outward attraction by adjoining drawn actually into the second liquid and thus air molecules that the first condition holds the integrity of the surface be destroyed. We and the surface tension is positive. While conclude, therefore, that a positive surface tenat a glass-oil surface a particle of liquid near sion is to be expected between all liquids that the surface may be supposed to be more

do not interdiffuse. strongly attracted by the neighboring glass If the particles in a colloid solution are to molecules than by the oil molecules in its be regarded as solid, we may expect to find vicinity, in which case the resultant attraction cases where the surface tension is positive is toward the glass, the potential energy of a and other cases where it is negative. Where liquid particle is less at the surface than in the it is positive there will be a tendency to floccuinterior of the liquid, and the surface tension late, for as two colloid particles come together is negative.

liquid particles move out from between them When liquid comes against liquid the case into the interior of the liquid, and the capillary is complicated by the mobility of particles on region surrounding the particles is thus deboth sides of the boundary. It seems probable, creased in volume, and the potential energy of however, taking an oil-water surface as an ex- the system is diminished. When, on the other hand, the surface tension is negative at the which were badly rusted in 1914, and which surface of a colloid particle, there will be no had been set out in a disease-free neighborflocculation, and the particles will not ap- hood in the spring of 1915 to test hibernation. proach each other near enough to crowd the A hypothesis is advanced which gives a realiquid out of the region of surface energy sonable explanation of the suspected hibernaaround either particle. This, of course, does tion. The rust often causes early defoliation not imply that there is any tendency in the of the currant plants, and this defoliation is latter case for the colloid particles to remain followed by a secondary production of foliage, in equilibrium equally diffused throughout the due to the development of winter buds. The liquid.

ARTHUR L. KIMBALL general occurrence of the rust on these secAMHERST COLLEGE

ondary leaves suggests that, allowing for the

two weeks' incubation period, the infection THE WHITE PINE BLISTER RUST; DOES THE must take place very early in their growth, and FUNGUS WINTER ON THE CURRANT? the question naturally follows: can such

started buds be infected at such an early stage In the work carried out in the Province of

in their development that if winter conditions Ontario during the last two years on this dis

set in soon after, the buds are still capable of ease, strong suspicions have been aroused that

surviving?

W. A. McCUBBIN the fungus may in some cases pass the winter

DivisioN OF BOTANY, on the currants themselves. Several lines of

EXPERIMENTAL FARM SYSTEM, evidence support these suspicions.

DOMINION OF CANADA, 1. The commencement of the currant stage

November, 1916 each spring here and there over large areas, without any apparent relation to the pines

PAMPHLET COLLECTIONS therein.

TO THE EDITOR OF SCIENCE: I note in Sci2. The similar yearly recurrence of the cur- ENCE for November 24, an article by Tracy I. rant rust in one particular district ten miles Storer from the University of California on by four miles in extent. In this area (a) the The Care of Pamphlet Collections” in which rust outbreaks do not bear any apparent rela- a type of cardboard case open at the back only tion to the pines; (b) the pines are very few and not larger than 12 X 8 X 24 inches” is in number; (c) many lots of these pines are recommended for this purpose. Permit me to small and their freedom from disease has

state that such cases differing only in size been established; (d) the evidence from five mine are 11 X 7 X 3 inches—have been in use lots of these young pines growing close to in- in my department since 1904. Several other fected currants indicates that the rust was not departments in the university had such cases introduced into this area until 1914, and that made after my design and they have been in therefore the prevalent currant stage of 1915 rather general use here since. I do not reand 1916 could not be due to pine blisters, member whether the idea is original with me which have not yet had time to mature.

or not. These cases are arranged alphabet3. The finding of six cases of the currant

ically by authors and the card index is by substage early in the year from one to two miles ject with the catch word first on the card. distant from any possible source of pine infec

CHAS. B. MORREY tion.

DEPARTMENT OF BACTERIOLOGY, 4. The occurrence of currant rust in 1916 on

OHIO STATE UNIVERSITY two adjacent plants in a large plantation. Early in the year these two only were rusted.

INDUSTRIAL LABORATORIES AND SCIENTIFIC The only four plants which were badly dis

INFORMATION eased here in 1915 included these two.

TO THE EDITOR OF SCIENCE: The undersigned 5. The occurrence of a rust outbreak on a committee on engineering of the General Complot of one hundred black currant plants mittee on Research, of the American Association for the Advancement of Science, feel that

SCIENTIFIC BOOKS it is timely to issue the following appeal to

Lectures on Ten British Mathematicians of the industrial research laboratories of the

the Nineteenth Century. By ALEXANDER country.

MACFARLANE. No. 17 of the Mathematical In the course of work done in the numerous

Monographs, edited by Mansfield Merriman industrial laboratories of America, many phys

and Robert S. Woodward. John Wiley and ical and commercial constants and data of

Sons, New York, 1916. great scientific interest and value are doubt

This posthumous publication contains most less arrived at, which may, for a certain

interesting biographies of ten of the leading period of time, constitute an asset of considerable commercial value to the particular cor

mathematicians of the nineteenth century in porations in question. During this period,

Great Britain, namely, of George Peacock,

Augustus De Morgan, Sir William Rowan every one recognizes the proprietary right of

Hamilton, George Boole, Arthur Cayley, the industrial laboratories to the retention of

William Kingdon Clifford, Henry John this information. A time frequently arrives, however, when

Stephen Smith, James Joseph Sylvester,

Thomas Penyngton Kirkman, Isaac Todhunter. such scientific information loses its commercial value (often by being duplicated in other

These sketches are a part of the lectures

given by Dr. Macfarlane at Lehigh Univerlaboratories), and just at this point we wish to impress upon the industries their obligation sity during the years 1901–04. “In a future

volume it is hoped to issue lectures on ten to enrich scientific literature with such facts

mathematicians whose main work was in physand data, which might otherwise be lost or

ics and astronomy.” The author's personal forgotten. Some of our industries have been reproached

acquaintance with some of these men, and with the suspicion of acting as sponges, in that

with intimate friends of them, enabled him to they absorb an immense amount of useful in

add personal touches which will be relished by

the reader. Particularly gratifying are the deformation from scientific literature without giving any return in kind. This suspicion tails about Boole and Kirkman, concerning

whom little had previously appeared in print. would be entirely removed if, from time to

The future historian of mathematics during time, scientific information which has ceased to be of commercial value were contributed by the nineteenth century will find the booklet them to its appropriate channel and thus be full of interesting material.

The lecturer's available to all scientific workers

aim was evidently to set forth the personalities throughout the world.

whose scientific achievements were already If any doubt exists as to the appropriate known to the listener. Hence the scientific rechannel for the publication of such scientific

searches of these men are not described, but data and communications, the general secre

merely mentioned. tary of the American Association for the Ad- Illuminating information is given in several vancement of Science, Dr. J. McKeen Cattell, of the biographies relating to Great Britain Garrison-on-Hudson, New York, will be glad

as “an examination-ridden country," and reto act as intermediary and to forward such lating to the effects of the theological tests communications to the proper scientific body. formerly demanded of candidates for degrees

A. E. KENNELLY,

and competitors for certain prizes. The opinJ. W. RICHARDS,

ions on the teaching of mathematics held by A. SAUVEUR,

some of the English mathematicians are valuA. N. TALBOT,

able at the present time when in the United C. C. THOMAS

States the mind-training-value of matheCAMBRIDGE, Mass.,

matical study is called into question. January 18, 1917

The booklet is manufactured in attractive

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form. Carelessness in the proof-reading is Dr. Glover M. Allen's “The Whalebone noticeable. Frequently letters are dropped Whales of New England” treats of the three out of words, their unceremonious departure genera and six species of baleen whales “inbeing accentuated by the blank spaces left be- habiting the waters off the New England hind. The description of Newton's fluxional coast,” with special reference to their habits, notation on page 9 is rendered unintelligible manner of occurrence, economic importance to one not already familiar with it by the and technical history. Two " keys ” are given omission in several instances of the necessary for their identification, one for stranded specidots. The spelling on page 35 of Clairaut as mens that can be approached and examined, “ Clairault” is unusual, to say the least. The the other for identification in life, based on statement, page 120, that it was in 1872 that a their characteristic actions, the presence or deputy professor was appointed at Oxford to absence of a fin on the back, and the size and carry on the work relinquished by Sylvester form of the spout. is evidently wrong, since Sylvester was ap- Following a few introductory pages of compointed to the Oxford position in 1883. It is ment on the classification of whales in general too bad that the editors of this book allowed and of the New England species in particular, the repetition of the erroneous statement that the author deals at length with each of the the name of Sylvester's father was Abraham living species, with a brief account of the Joseph Sylvester. As recently stated by sev- single fossil species, long known from a few eral writers, the Sylvester" did not be- vertebræ and other fragmentary remains long to the father, but was assumed by an found at Gay Head, Marthas Vineyard. The elder brother of the mathematician who had North Atlantic right whale (Eubalona come to the United States, and later by the glacialis) is of special interest historically on mathematician himself. The father's name account of its having been the basis of the was Abraham Joseph. The editors might also early New England whale fishery. This phase have corrected a mistake thus far almost uni- of the subject is presented in considerable deversal, to the effect that Peaucellier was the tail (pp. 131–172), with many quaint extracts first to devise an instrument for drawing a from early colonial records. perfect straight line. It is a matter of great The species treated are: (1) North Atlantic historical interest that a Frenchman by the right whale (Eubalæna glacialis), (2) common name of Sarrut achieved this several years be finback (Balænoptera physalus), (3) pollack fore Peaucellier, and in a manner quite differ- whale (B. borealis), (4) blue whale (B. musent. An account of it will be found in the culus), (5) little piked whale (B. acuto-rosComptes Rendus, Vol. 36, 1853, page 1036. tratus), (6) Atlantic humpback (Megaptera Attention to Sarrut was called in 1905 by G.T. nodosa). A methodical and concise account Bennett of Emmanuel College, Cambridge, in of each is given under appropriate subheadan article published in the Philosophical ings, beginning with “history and nomenclaTransactions, 6th S., Vol. 9, page 803. Ben- ture,” followed by descriptions of their externett gives interesting historical details, and nal and osteological characters, habits and also noteworthy developments of his own. food, seasons of occurrence, pursuit and eco

nomic products, enemies and parasites. Five

FLORIAN CAJORI COLORADO COLLEGE,

of the species are illustrated by full-page plates COLORADO SPRINGS, COLO.

of the external form, drawn to scale from

careful measurements. Outline drawings of The Whalebone Whales of New England. By skulls are given in another plate, several

GLOVER M. ALLEN. Memoirs of the Boston photographic views of whales in another, and Society of Natural History, Vol. 8, No. 2, vertebræ and other fossil remains from the pp. 107–322, pls. 8–15, text-figs. 1-12. Miocene deposits of Gay Head in another. September, 1916.

The monograph thus forms a valuable addition to the literature of the subject, consti- strength of boric acid. These buffers regulate tuting, as it does, the first attempt to treat the reaction of sea water in a manner similar comprehensively this important part of the to the way in which bicarbonates and phosmarine mammal fauna of New England, and phates regulate the reaction of blood. . is a highly satisfactory summation of present An Apparent Correspondence between the knowledge of the subject. A bibliography of Chemistry of Igneous Magmas and of Organic six pages (about 100 titles) gives references to Metabolism: Henry S. Washington, Geophysthe technical literature cited in the text, in ical Laboratory, Carnegie Institution of Washaddition to which are numerous footnote and ington. The object is to call attention to other references in the text to historical what appears to be a congruous relation of records relating to the distribution and occur- two pairs of elements in the organic world; rence of the species in New England waters, it would appear that iron and sodium are necfrom early colonial times to the present. essary for animal metabolism, while magne

J. A. ALLEN sium and potassium are essential to vegetable AMERICAN MUSEUM OF NATURAL HISTORY

metabolism.

The Oaks of America: William Trelease, PROCEEDINGS OF THE NATIONAL

Department of Botany, University of Illinois. ACADEMY OF SCIENCES

A summary of a manuscript now prepared for

submission to the academy for publication as The eleventh number of Volume 2 of the

one of its scientific memoirs. 354 species of Proceedings of the National Academy of Sci

oaks, of which about one half are new, are ences contains the following articles:

recognized. The relations to fossil oaks are Path Differences within which Spectrum

pointed out. Interferences are Observable: Carl Barus, De

A Set of Independent Postulates for Cyclic partment of Physics, Brown University. The

Order: Edward V. Huntington, Department method of observing interferences in the

of Mathematics, Harvard University. Five zeroth, first, second, third, and even fourth order, successively, without essential change postulates are given for cyclic order.

A New Method of Studying Ideational and of the parts of the apparatus is noteworthy.

Allied Forms of Behavior in Man and Other The present experiments furnish a striking

Animals : Robert M. Yerkes, Psychological example of the uniform breadth of the strip Laboratory, Harvard University. A descripof spectrum carrying the fringes, quite apart

tion of the author's method of multiple choices from the dispersion of the spectrum.

for the deduction of reactive tendencies and Non-Reversed Spectra of Restricted Coin

the study of their rôle in the attempted solucidence: Carl Barus, Department of Physics,

tion of certain types of problem. The method Brown University. The method, apart from

involves the presentation to the subject of a any practical outcome, is worth pursuing because of the data it will furnish of the width

problem or series of problems whose rapid and of the strip of spectrum carrying interference complete solution depends upon ideational fringes under any given conditions.

processes. The Equilibrium between Acids and Bases

Electrical Conduction in Dilute Amalgams: in Sea Water: Lawrence J. Henderson and

Gilbert N. Lewis and Thomas B. Hine, DeEdwin J. Cohn, Wolcott Gibbs Memorial Labo- partment of Chemistry, University of Caliratory, Harvard University.

The ocean,

fornia. The resistance of amalgams of which, because of the presence of free carbonic lithium, sodium and potassium is studied at acid, was originally acid, and which has been constant pressure and shows extraordinary becoming more alkaline from the accumulation differences; the resistances at constant averof basic material, is at present in an epoch age atomic volume are also calculated and where the growing alkalinity is checked by the found to differ materially from those at conbuffer action of acids of approximately the stant pressure.

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